PHP foreach loop to parse XML by attribute

I have following XML file:

  <SHOPITEM>
    <FRAMESIZE>MD</FRAMESIZE>
    <CODE>032,00</CODE>
    <PRODUCT>POINT</PRODUCT>
    <COLOR>red / green</COLOR>
        <PRODUCT_VARIANT id="2">
          <FRAMESIZE>LG</FRAMESIZE>
          <CODE>032,01</CODE>
          <PRODUCT>POINT</PRODUCT>
          <COLOR>black / yellow</COLOR>
        </PRODUCT_VARIANT>
  </SHOPITEM>

Here is my current PHP code to loop through XML:

    foreach($xml->SHOPITEM as $izdelki)

{   

$artikel = (array)$izdelki;
$izdelek = array();
echo $artikel['PRODUCT'] . '-' . $artikel['CODE'] . '-' . $artikel['FRAMESIZE'] . '<br>';

    //this is not working
    foreach($xml->SHOPITEM->PRODUCT_VARIANT as $p_variant)
        {
            //get main product code 032,00
            echo  $artikel['CODE']; 

            //get current attribute (id) number
            echo $xml->SHOPITEM->PRODUCT_VARIANT['id']


            echo $p_variant["PRODUCT"] . '<br>';

        }

}  

This works, except the "this is not working part". :) It is possible to loop a foreach in foreach to get data from ?